vBulletin 4.1.0 is still actually beta, which you will see when you go to download it. I don't know why they left this out of their announcement, since they usually discourage customers from installing beta software.

vBulletin 4.1 is also now available as a public Beta. This can be downloaded from the vBulletin Members Area at: http://members.vbulletin.com
Please note:
* We do not provide support for Beta versions
* Some minor bugs remain unresolved at this time, and we do not recommend beta software to be installed on production sites.
* We always recommend that you back up your database fully before attempting to install beta software.

I've put together a timeline. This is another debacle that we can blame IB for because apparently they released 4.1.0 before it finished QA, so they called it Beta 1, even though they didn't intend for a true beta period. Here's what happened:

But a bug is found and they remove the download in a few hours after release.

The announcement doesn't acknowledge that it was different than Beta 1, but I personally check the download area anyway. I can only download Beta 1. This causes a belief that it was just another announcement to remind people.

Dec 1

VaultWiki 3.0.7 is released

Dec 2

You ask if 3.0.7 is also compatible with 4.1.0 (not beta).

I personally check the vBulletin Download area, and 4.1.0 (not beta) is still removed. I post my response.